The Retinoblastoma protein is a nuclear phosphoprotein product of the RB1 gene. It is. Retinoblastoma is a tumor suppressor because of its control over the cell cycle.
Unregulated cellular proliferation underlies neoplastic transformation and tumorigenesis. Tumor cells typically have acquired some genetic damage to the regulators of the cell cycle. The Retinoblastoma protein (Rb), is a cell cycle regulator protein that when active, arrests cells in G1. Rb orchestrates signals controlling of cell cycle progression, and cancer cells almost invariably have genetic alterations of Retinoblastoma protein (Rb) pathway components. Cyclin-dependent kinase (Cdk) phosphorylation of the Retinoblastoma protein (Rb) drives cell proliferation by inhibiting the formation of complexes between Rb and E2F transcription factors and other regulatory proteins. The mechanism of Rb inactivation is largely unknown.
Considering the high prevalence of Rb pathway lesions in cancer, there is clear motivation for therapeutics that target pathway components to inhibit aberrant proliferation.